In a patient with clinically significant cardiovascular disease, (ASA III or IV), the recommended maximum dosage of epinephrine is 0.04mg (normally 0.2mg in a healthy patient)†, and the recommended maximum dosage of Levonordefrin is 0.2mg (normally 1.0mg in a healthy patient). By turning this feature on, the reduced maximum dosage will be applied to all calculations.
†Malamed, Stanley F. Handbook of Local Anesthesia, pg 45, 6th Edition. Mosby, 2013.